Light-emitting diode and manufacturing method therefor

ABSTRACT

A light-emitting diode and a manufacturing method therefor are disclosed. The light-emitting diode comprises: a first conductive semiconductor layer; at least two light-emitting units arranged by being spaced from each other on the first conductive semiconductor layer, respectively including an active layer and a second conductive semiconductor layer, and including one or more contact holes through which the first conductive semiconductor layer is partially exposed; an additional contact area located between the light-emitting units; a second electrode making ohmic contact with the second conductive semiconductor layer; a lower insulation layer; and a first electrode making ohmic contact with the first conductive semiconductor layer through the contact holes of each of the light-emitting units and the additional contact area.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application is a continuation of U.S. patent applicationSer. No. 15/501,815, filed on Feb. 3, 2017, which is a 35 U.S.C. § 371National Stage application of PCT Patent Application No.PCT/KR2015/008150, filed on Aug. 4, 2015, which claims the benefits andpriorities of Korean Patent Application No. 10-2014-0100364, filed onAug. 5, 2014 and Korean Patent Application No. 10-2015-0109959, filed onAug. 4, 2015.

TECHNICAL FIELD

Exemplary embodiments of the present disclosure relate to a lightemitting diode and a method of manufacturing the same, and moreparticularly, to a light emitting diode, which can minimize reduction inluminous area and has high current spreading efficiency, and a method ofmanufacturing the same.

BACKGROUND

A light emitting diode refers to an inorganic semiconductor deviceconfigured to emit light through recombination of electrons and holes,and in recent years, light emitting diodes using nitride semiconductorshaving direct transition characteristics have been developed andmanufactured in the art.

Light emitting diodes can be classified into a lateral type lightemitting diode and a flip-chip type light emitting diode depending uponlocations of electrodes, a connection structure of the electrodes toexternal leads, and the like. Recently, with increasing demand for ahigh power light emitting diode, there is increasing demand for a largeflip-chip type light emitting diode having good heat dissipationefficiency.

SUMMARY

Exemplary embodiments of the present disclosure provide a light emittingdiode having improved current spreading efficiency.

Exemplary embodiments of the present disclosure provide a method ofmanufacturing a light emitting diode, which can minimize removal of anactive layer while improving current spreading efficiency, and canprovide a simple process.

In accordance with one aspect of the present disclosure, a lightemitting diode includes: a first conductive type semiconductor layer; atleast two light emitting units disposed on the first conductive typesemiconductor layer to be spaced apart from each other and eachincluding an active layer, a second conductive type semiconductor layer,and at least one contact hole formed through the second conductive typesemiconductor layer and the active layer so as to expose a portion ofthe first conductive type semiconductor layer; an additional contactregion disposed between the light emitting units and partially exposingthe first conductive type semiconductor layer; a first electrode formingohmic contact with the first conductive type semiconductor layer throughthe contact hole and the additional contact region of each of the lightemitting units; a second electrode disposed on each of the lightemitting units and forming ohmic contact with the second conductive typesemiconductor layer; and a lower insulation layer covering a sidesurface of the first conductive type semiconductor layer, the lightemitting units, and the second electrodes, wherein the lower insulationlayer includes a first opening exposing the contact hole and theadditional contact region and a second opening partially exposing thesecond electrode, and the first and second electrode are insulated fromeach other.

The first electrode may also form ohmic contact with the firstconductive type semiconductor layer through the additional contactregion, thereby improving current spreading efficiency of the lightemitting diode.

The additional contact region may be disposed in a region between atleast four light emitting units, specifically in a region in which onecorner of each of the at least four light emitting units meets cornersof other three light emitting units.

Distances from a center of the additional contact region to centers ofthe at least four light emitting units may be the same.

The contact hole may be disposed in a central region of each of thelight emitting units.

The light emitting diode may further include one or more connectionlayers electrically connecting the second electrode disposed on one ofthe light emitting units to the second electrode disposed on anotherlight emitting unit adjacent to the one light emitting unit.

The first electrode may cover at least part of the lower insulationlayer and may contact the first conductive type semiconductor layerthrough the first opening.

The first electrode may further cover the first conductive typesemiconductor layer and side surfaces of the light emitting units andmay be insulated by the lower insulation layer.

In other exemplary embodiments, the light emitting diode may furtherinclude an upper insulation layer at least partially covering the firstelectrode, wherein the upper insulation layer may include a thirdopening partially exposing the first electrode and a fourth openingpartially exposing the second electrode.

The light emitting diode may further include a first pad disposed on thethird opening and electrically connected to the first electrode; and asecond pad disposed on the fourth opening and electrically connected tothe second electrode.

The light emitting diode may further include a heat dissipation paddisposed on the upper insulation layer.

The heat dissipation pad may be disposed between the first pad and thesecond pad.

In accordance with another aspect of the present disclosure, a method ofmanufacturing a light emitting diode includes: forming a firstconductive type semiconductor layer, an active layer and a secondconductive type semiconductor layer on a substrate; forming at least twolight emitting units each including the second conductive typesemiconductor layer, the active layer and contact holes, and anadditional contact region disposed in a region between the lightemitting units by partially removing the second conductive typesemiconductor layer and the active layer, while forming a secondelectrode on each of the light emitting units so as to form ohmiccontact with the second conductive type semiconductor layer; forming alower insulation layer covering a side surface of the first conductivetype semiconductor layer, the light emitting units, and the secondelectrodes; and forming a first electrode forming ohmic contact with thefirst conductive type semiconductor layer through the contact holes andthe additional contact region, wherein the contact holes are formedthrough the second conductive type semiconductor layer and the activelayer so as to expose a portion of the first conductive typesemiconductor layer, the first conductive type semiconductor layer isexposed to a lower side of the additional contact region, and the lowerinsulation layer includes first openings exposing the contact holes andthe additional contact region, and second openings partially exposingthe second electrodes.

The light emitting units may include at least four light emitting unitsand the additional contact region may be disposed in a region surroundedby the at least four light emitting units.

The additional contact region may be disposed in a region in which onecorner of each of the at least four light emitting units meets cornersof other three light emitting units.

The method may further include forming one or more connection layerselectrically connecting the second electrode disposed on one of thelight emitting units to the second electrode disposed on another lightemitting unit adjacent to the one light emitting unit.

The connection layers may be formed simultaneously with the firstelectrode.

Forming the first electrode may include filling the first openings withthe first electrode such that the first electrode contacts the firstconductive type semiconductor layer through the first openings.

The method may further include forming an upper insulation layer atleast partially covering the first electrode after formation of thefirst electrode, wherein the upper insulation layer may include a thirdopening partially exposing the first electrode and a fourth openingpartially exposing the second electrode.

The method may further include forming a first pad on the third openingso as to be electrically connected to the first electrode and a secondpad on the fourth opening so as to be electrically connected to thesecond electrode.

The method may further include forming a heat dissipation pad on theupper insulation layer.

The first pad, the second pad and the heat dissipation pad may be formedat the same time.

In accordance with a further aspect of the present disclosure, a lightemitting diode includes: a light emitting structure including a firstconductive type semiconductor layer, an active layer, and a secondconductive type semiconductor layer, the light emitting structureincluding one or more mesas disposed on the first conductive typesemiconductor layer to be spaced apart from each other and eachincluding the active layer and the second conductive type semiconductorlayer and having at least one contact hole formed through the secondconductive type semiconductor layer and the active layer so as to exposea portion of the first conductive type semiconductor layer; a firstelectrode forming ohmic contact with the first conductive typesemiconductor layer through the contact holes of the mesas; a currentspreading layer disposed on the mesas and forming ohmic contact with thesecond conductive type semiconductor layer; a second electrode disposedon the current spreading layer; and an insulation layer covering thelight emitting structure and the current spreading layer, and includingopenings partially exposing the first and second electrodes, whereineach of the contact holes includes a plurality of main contact holesspaced apart from each other and a plurality of secondary contact holesconnecting the main contact holes to each other and having a narrowerwidth than the main contact holes.

The light emitting diode may further include a current blocking layerdisposed under the current spreading layer, wherein the current blockinglayer may be disposed below the second electrode so as to correspond toa location of the second electrode.

The current spreading layer may include a conductive oxide.

The current spreading layer may include a lower current spreading layerand an upper current spreading layer disposed on the lower currentspreading layer.

The current spreading layer may be formed of a conductive oxide dopedwith a metallic dopant.

The light emitting diode may further include a first pad and a secondpad disposed on the insulation layer and electrically connected to thefirst electrode and the second electrode, respectively, wherein thefirst and second pad are spaced apart from each other.

The first electrode may include a first ohmic contact electrode disposedunder the first pad; a second ohmic contact electrode including a mainelectrode disposed under the first pad and an extension electrodeextending from the main electrode to a portion under a region betweenthe first pad and the second pad; and a third ohmic contact electrodedisposed under the first pad and forming ohmic contact with theadditional contact region.

The main electrode of the second ohmic contact electrode may be disposedin the main contact holes and the extension electrode of the secondohmic contact electrode may be disposed in the main contact holes andthe secondary contact holes.

A portion of the extension electrode disposed in the main contact holesmay have a greater width than a portion of the extension electrodedisposed in the secondary contact holes and may be disposed under theregion between the first pad and the second pad.

The extension electrode of the second ohmic contact electrode may becovered by the insulation layer.

The second electrode may include a first connection electrode disposedunder the second pad; and a second connection electrode including a mainelectrode disposed under the second pad and an extension electrodeextending from the main electrode towards the first pad.

The extension electrode of the second connection electrode may extend toa portion under a region between the first pad and the second pad.

The extension electrode of the second connection electrode may extend toa region under the first pad.

The extension electrode may have a smaller width than the mainelectrode.

The extension electrode may be covered by the insulation layer.

The mesa may be composed of a plurality of mesas; the light emittingstructure may be disposed between the mesas and further include anadditional contact region partially exposing the first conductive typesemiconductor layer; and the first electrode disposed on the additionalcontact region may be exposed through the openings of the insulationlayer.

The insulation layer may include a lower insulation layer and an upperinsulation layer disposed on the lower insulation layer.

The lower insulation layer may have a greater thickness than the upperinsulation layer, and the upper insulation layer may include adistributed Bragg reflector.

The lower insulation layer may be formed of SiO₂ and have a thickness of0.2 μm to 1.0 μm, and the upper insulation layer may have a stackstructure in which TiO₂/SiO₂ layers are alternately stacked one aboveanother.

At least part of the first electrode and the second electrode mayfurther cover an upper surface of the lower insulation layer around theopenings of the lower insulation layer to be interposed between thelower insulation layer and the upper insulation layer.

According to exemplary embodiments, a light emitting diode has anadditional contact region formed in a region surrounded by lightemitting units, thereby improving current spreading efficiency andluminous uniformity. As a result, the light emitting diode has improvedluminous efficacy and reliability.

In addition, the additional contact region is formed in a process offorming the light emitting units, thereby providing a light emittingdiode having improved current spreading efficiency without separatelyperforming an additional process.

Further, the light emitting diode includes electrodes includingextension portions extending to a region between a first pad and asecond pad, thereby improving current spreading efficiency.

Furthermore, the light emitting diode includes a multilayer structure ofcurrent spreading layers, thereby improving current spreading efficiencyand luminous efficacy.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 to FIG. 3 are a plan view and cross-sectional views of a lightemitting diode according to one exemplary embodiment of the presentdisclosure.

FIG. 4 is a plan view of a light emitting diode according to anotherexemplary embodiment of the present disclosure.

FIG. 5A to FIG. 11B are plan views and cross-sectional viewsillustrating a method of manufacturing a light emitting diode accordingto a further exemplary embodiment of the present disclosure.

FIG. 12 to FIG. 16 are plan views and cross-sectional views of a lightemitting diode according to yet another exemplary embodiment of thepresent disclosure.

FIG. 17 is a cross-sectional view of a light emitting diode according toyet another exemplary embodiment of the present disclosure.

FIG. 18A to FIG. 25B are plan views and cross-sectional viewsillustrating a method of manufacturing a light emitting diode accordingto yet another exemplary embodiment of the present disclosure.

FIG. 26 is an exploded perspective view of a lighting apparatus to whicha light emitting diode according to one exemplary embodiment of thepresent disclosure is applied.

FIG. 27 is a cross-sectional view of one example of the displayapparatus to which the light emitting diode according to the exemplaryembodiment of the present disclosure is applied.

FIG. 28 is a cross-sectional view of another example of the displayapparatus to which the light emitting diode according to the exemplaryembodiment of the present disclosure is applied.

FIG. 29 is a cross-sectional view of a headlight to which a lightemitting diode according to one exemplary embodiment of the presentdisclosure is applied.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of the present disclosure will bedescribed in detail with reference to the accompanying drawings. Thefollowing embodiments are provided by way of example so as to fullyconvey the spirit of the present disclosure to those skilled in the artto which the present disclosure pertains. Accordingly, the presentdisclosure is not limited to the embodiments disclosed herein and canalso be implemented in different forms. In the drawings, widths,lengths, thicknesses, and the like of elements can be exaggerated forclarity and descriptive purposes. When an element is referred to asbeing “disposed above” or “disposed on” another element, it can bedirectly “disposed above” or “disposed on” the other element, orintervening elements can be present. Throughout the specification, likereference numerals denote like elements having the same or similarfunctions.

Recently, for an N-type electrode, structures in which an N-typeelectrode pad includes linear extension portions are proposed. Suchlinear extension portions are formed along a region of an N-typesemiconductor layer exposed by removing the active layer throughetching, whereby a luminous area of the light emitting diode is deceasedby a removed portion of the active layer. Moreover, when the extensionportions exhibit high resistance, the extension portions have alimitation in current spreading. Moreover, since a reflective electrodeis restrictively disposed on a P-type semiconductor layer, substantiallight loss occurs due to the pads and the extension portions instead oflight reflection by the reflective electrode. Further, current crowdingoccurs depending upon locations of the N-type electrode and a P-typeelectrode, thereby forming a region exhibiting very low luminousefficacy. Moreover, a region for exposing the N-type semiconductor layeroccupies a relatively large area in order to form the N-type electrode.This structure causes reduction in luminous area, thereby deterioratingoverall luminous efficacy and luminous intensity of the light emittingdiode.

In addition to such implementations, light emitting diodes havingvarious electrode structures are disclosed in the art. However,according to such implementations, upon operation of the light emittingdiode through application of electric current, current crowding occursaround the N-type electrode, thereby causing concentration of lightemission around the N-type electrode.

Therefore, there is a need for a light emitting diode having anelectrode structure and a semiconductor layer structure that secure goodcurrent spreading efficiency and a uniform luminous pattern of the lightemitting diode.

FIG. 1 to FIG. 3 are a plan view and cross-sectional views of a lightemitting diode according to one exemplary embodiment of the presentdisclosure. FIG. 2 is a cross-sectional view taken along line A-A ofFIG. 1 and FIG. 3 is a cross-sectional view taken along line B-B ofFIG. 1. For convenience of description, some reference numerals areomitted in FIG. 1. Components denoted by reference numerals relating tothe plan view will be described in more detail in exemplary embodimentsdescribed with reference to FIG. 5A to FIG. 11B.

Referring to FIG. 1 to FIG. 3, a light emitting diode according to oneexemplary embodiment of the present disclosure includes a light emittingstructure 120, which includes a first conductive type semiconductorlayer 121, an active layer 123 and a second conductive typesemiconductor layer 125, light emitting units 120 c, a first electrode140, and second electrodes 131. The light emitting diode may furtherinclude a substrate 110, a lower insulation layer 151, an upperinsulation layer 153, a connection layer 133, a first pad 161, and asecond pad 163.

The substrate 110 may be any substrate that allows growth of the lightemitting structure 120 thereon, and may include, for example, a sapphiresubstrate, a silicon carbide substrate, a silicon substrate, a galliumnitride substrate, and an aluminum nitride substrate. In this exemplaryembodiment, the substrate 110 may be a patterned sapphire substrate PSS.

In the light emitting diode, the substrate 110 may be omitted. In astructure wherein the substrate 110 is used as a growth substrate forthe light emitting structure, the substrate 110 may be separated orremoved from the light emitting structure 120 by a technique known to aperson having ordinary knowledge in the art (hereinafter, ‘those skilledin the art’). The substrate 110 may be separated or removed from thelight emitting structure 120 by physical and/or chemical methods, forexample, laser lift-off, chemical lift-off, stress lift-off, orpolishing.

The light emitting structure 120 may include the first conductive typesemiconductor layer 121, the active layer 123 disposed on the firstconductive type semiconductor layer 121, and the second conductive typesemiconductor layer 125 disposed on the active layer 123. In addition,the light emitting diode may include a light emitting unit 121 cdisposed on the first conductive type semiconductor layer 121 andincluding the active layer 123 and the second conductive typesemiconductor layer 125. The light emitting unit 121 c may be providedin plural and each of the light emitting units 121 c may include one ormore contact holes 127. The light emitting diode may include anadditional contact region 129 formed in a region surrounded by the lightemitting units 121 c.

The first conductive type semiconductor layer 121, the active layer 123and the second conductive type semiconductor layer 125 may include aIII-V based compound semiconductor, for example, a nitride semiconductorsuch as (Al, Ga, In)N. The first conductive type semiconductor layer 121may include an n-type dopant (for example, Si) and the second conductivetype semiconductor layer 125 may include a p-type dopant (for example,Mg), or vice versa. The active layer 123 may include a multi-quantumwell (MQW) structure.

The light emitting unit 121 c includes the active layer 123 and thus canbe defined as a luminous region in operation of the light emittingdiode. Further, the light emitting diode may include at least two lightemitting units 121 c and the additional contact region 129 may be formedin a separation region between the at least two light emitting units 121c. For example, as shown in the drawings, the light emitting diodeaccording to this exemplary embodiment may include at least four lightemitting units 121 c, which are separated from one another to form aseparation region 128 therebetween. Particularly, in the separationsregion 128, a region surrounded by the four light emitting units 121 cmay be defined as the additional contact region 129. Each of the lightemitting units 121 c may further include a portion of the firstconductive type semiconductor layer 121 in addition to the active layer123 and the second conductive type semiconductor layer 125. Here, itshould be understood that other implementations are also possible andthe additional contact region 129 may be formed in a separation regionbetween two or more light emitting units 121 c.

Each of the light emitting units 121 c may include one or more contactholes 127, which may be formed by partially removing the secondconductive type semiconductor layer 125 and the active layer 123.Accordingly, the first conductive type semiconductor layer 121 may bepartially exposed through the contact holes 127. Although the number andlocations of the contact holes 127 in the light emitting units 120 c arenot particularly limited, for example, the contact hole 127 may bedisposed in a central region of each of the light emitting units 120 c.

As described below, the first electrode 140 may form ohmic contact withthe first conductive type semiconductor layer 121 through the contactholes 127. Accordingly, current spreading efficiency and a luminouspattern of the light emitting diode can be regulated depending upon thelocations and number of contact holes 127. For example, with thestructure wherein each of the contact holes 127 is disposed in thecentral region of the light emitting unit 120 c, the light emittingstructure allows uniform current spreading to each of the light emittingunits 120 c. However, it should be understood that the number andlocations of the contact holes 127 shown in the drawings are providedfor illustration only and may be designed in various way inconsideration of current spreading efficiency.

On the other hand, the additional contact region 129 may be disposed ina separation region between at least two light emitting units 120 c.Particularly, as shown in the drawings, the additional contact region129 may be disposed in a region in which one corner of each of the atleast four light emitting units 120 c meets corners of other three lightemitting units 120 c. This is applied to the structure wherein each ofthe light emitting units 120 c has a rectangular planar shape, and mayalso be applied to other structures wherein the light emitting units 120c have other shapes instead of the rectangular planar shape. Forexample, in a structure wherein the additional contact region 129 issurrounded by five or more light emitting units 120 c, the additionalcontact region 129 may be disposed in a region in which one corner ofeach of the light emitting units 120 c meets corners of other lightemitting units 120 c.

It should be understood that other implementations are also possible andthe additional contact region 129 may be disposed between at least 2light emitting units 120 c, as described above. For example, in thestructure wherein the additional contact region 129 is formed betweentwo light emitting units 120 c, the additional contact region 129 may beplaced on an imaginary line connecting the contact hole of one lightemitting unit to the contact hole of the other light emitting unit. Inthis structure, in order to form a space for formation of the additionalcontact region 129, side surfaces of the light emitting units 120 c maybe partially removed along the additional contact region 129.

As described below, the first electrode 140 forms ohmic contact with thefirst conductive type semiconductor layer 121 not only through thecontact holes 127 but also through the additional contact region 129.With the structure wherein the first conductive type semiconductor layer121 also forms ohmic contact with the first electrode 140 through theadditional contact region 129 dispose in the separation region betweenat least two light emitting units 120 c, the light emitting diode canhave further improved current spreading efficiency.

Particularly, in this exemplary embodiment, distances from the center ofthe additional contact region 129 to the centers of the four lightemitting units 120 c may be substantially the same, and the contact hole127 may be disposed in a central region of each of the light emittingunits 120 c. With this structure, the light emitting diode can haveimproved current spreading efficiency by the additional contact region129 and the contact holes 127, thereby improving overall luminousuniformity.

Furthermore, the luminous region is divided by the light emitting units120 c and a contact region between the first conductive typesemiconductor layer 121 and the first electrode 140 is disposed in aregion between the light emitting units 120 c, whereby the lightemitting diode can have reduced forward voltage Vf.

In this exemplary embodiment, the light emitting diode is illustrated asincluding four light emitting units 120 c. However, it should beunderstood that other implementations are also possible and lightemitting diodes according to other exemplary embodiments of the presentdisclosure may include at least two or at least five light emittingunits 120 c.

For example, as shown in FIG. 4, a light emitting diode including morelight emitting units 120 c also falls within the scope of the inventiveconcept of the present disclosure. Referring to FIG. 4, the lightemitting diode may include sixteen light emitting units 120 c andadditional contact regions 129 formed in regions each surrounded by fouradjacent light emitting units 120 c. Thus, according to exemplaryembodiments of the present disclosure, the light emitting diodeincluding more light emitting units 120 c can have improved currentspreading efficiency.

Referring again to FIG. 1 to FIG. 3, the second electrode 131 isdisposed on each of the light emitting units 120 c and may partiallycover an upper surface of the second conductive type semiconductor layer125 while forming ohmic contact therewith. Particularly, the secondelectrodes 131 may cover most of the upper surface of the secondconductive type semiconductor layer 125, whereby light emitted from theactive layer 123 can be effectively emitted and each of the lightemitting units 120 c can have improved current spreading efficiency.

The second electrode 131 is not formed in a region corresponding to thecontact hole 127 and thus is insulated from the first conductive typesemiconductor layer 121. Each the contact hole 127 may be generallyformed in a central region of each the second electrode 131. With thisstructure, in operation of the light emitting diode, when electriccurrent is applied to the first electrode 140 and the second electrodes131 connected to each other through the contact holes 127, the lightemitting diode can have improved current spreading efficiency.

The second electrodes 131 may include a reflective layer and a coverlayer covering the reflective layer.

As described above, the second electrodes 131 can serve to reflect lightwhile forming ohmic contact with the second conductive typesemiconductor layer 125. Accordingly, the reflective layer may include ametal having high reflectivity and capable of forming ohmic contact withthe second conductive type semiconductor layer 125. For example, thereflective layer may include at least one of Ni, Pt, Pd, Rh, W, Ti, Al,Ag, and Au. Further, the reflective layer may be composed of a singlelayer or multiple layers.

The cover layer can prevent interdiffusion between the reflective layerand other materials while preventing damage to the reflective materialthrough diffusion of external material to the reflective layer. Thus,the cover layer may be formed to cover a lower surface and a sidesurface of the reflective layer. The cover layer may be electricallyconnected to the second conductive type semiconductor layer 125 togetherwith the reflective layer and thus can act as an electrode together withthe reflective layer. The cover layer may include at least one of, forexample, Au, Ni, Ti, and Cr, and may be composed of a single layer ormultiple layers.

Alternatively, the second electrodes 131 may include a transparentconductive material. The transparent conductive material can form ohmiccontact with the second conductive type semiconductor layer 125 and mayinclude at least one of, for example, ITO, ZnO, IZO and Ni/Au. In thestructure wherein the second electrodes 131 include a transparentconductive material, the upper insulation layer 153 described below mayinclude a reflective layer in order to provide a reflection function.

Referring again to FIG. 1 to FIG. 3, the light emitting diode mayfurther include a lower insulation layer 151. The lower insulation layer151 may at least partially cover the light emitting units 120 c and areflective metal layer 131. In addition, the lower insulation layer 151may be formed to cover side surfaces of the contact holes 127 whileexposing lower surfaces of the contact holes 127 such that the firstconductive type semiconductor layer 121 can be partially exposed throughthe contact holes 127. Furthermore, the lower insulation layer 151 maycover a side surface of the light emitting structure 120.

The lower insulation layer 151 may include first openings disposedcorresponding to the contact holes 127 and the additional contact region129, and second openings partially exposing the second electrodes 131.The first conductive type semiconductor layer 121 may be electricallyconnected to the first electrode 140 through the first openings and thecontact holes 127. The second electrodes 131 may be electricallyconnected to the second pad 163 through the second openings. Inaddition, the second openings may provide regions in which theconnection layer 133 is formed.

The lower insulation layer 151 may include an insulation material, forexample, SiO₂ or SiN_(x). Furthermore, the lower insulation layer 151may have a multilayer structure and may include a distributed Braggreflector in which material layers having different refractive indicesare alternately stacked one above another. Particularly, in thestructure wherein the second electrodes 131 include a transparentconductive material, the lower insulation layer 151 may include areflective material or the distributed Bragg reflector. With thisstructure, the lower insulation layer 151 serves to reflect light,thereby improving luminous efficacy of the light emitting diode.

The first electrode 140 may be disposed on the light emitting structure120 and may at least partially cover the light emitting units 120 c. Inaddition, the first electrode 140 may be disposed on the contact holes127 and the additional contact region 129 to form ohmic contact with thefirst conductive type semiconductor layer 121. The first electrode 140is not formed on the second openings of the lower insulation layer 151,that is, in regions to which the second electrodes 131 are exposed.

The first electrode 140 may be formed to cover the entirety of the lightemitting units excluding some region of the lower insulation layer 151,and particularly, may be formed to cover the side surfaces of the lightemitting units 120 c and the side surface of the first conductive typesemiconductor layer 121.

With the structure wherein the first electrode 140 is formed to coverthe entirety of the light emitting units excluding some region, thelight emitting diode can have further improved current spreadingefficiency. Furthermore, since the first electrode 140 can cover aportion not covered by the second electrodes 131, the first electrode140 can reflect light traveling toward the side surface of the lightemitting structure 120, thereby improving luminous efficacy of the lightemitting diode. Furthermore, the first electrode 140 is also formed onthe side surface of the light emitting structure 120 and thus canreflect light emitted through the side surface of the active layer 123,thereby improving luminous efficacy of the light emitting diode.

The first electrode 140 forms ohmic contact with the first conductivetype semiconductor layer 121 and can serve to reflect light, asdescribed above. The first electrode 140 may be composed of a singlelayer or multiple layers including at least one of Ni, Pt, Pd, Rh, W,Ti, Al, Ag and Au. For example, the first electrode 140 may include ahighly reflective metal layer such as an Al layer, and the highlyreflective metal layer may be bonded to a bonding layer formed of Ti, Cror Ni.

The first electrode 140 may be insulated from the second electrodes 131and the side surface of the light emitting structure 120, for example,by the lower insulation layer 151 interposed between the first electrode140 and the second electrodes 131.

The light emitting diode may further include the connection layer 133.

The connection layer 133 may electrically connect the second electrode131 disposed on one of the light emitting units 120 c to the secondelectrode 131 disposed on another light emitting unit 120 c adjacent tothe one light emitting unit. For example, the connection layer 133 mayelectrically connect the second electrodes 131 disposed on adjacentlight emitting units 120 c to each other through at least two secondopenings of the lower insulation layer 151.

The connection layer 133 may electrically connect the second electrodes131 disposed on at least two light emitting units 120 c to each other,and may electrically connect the second electrodes 131 disposed on allof the light emitting units 120 c to each other. For example, as shownin the drawings, the connection layer 133 may connect two light emittingunits 120 c linearly arranged in the vertical direction to each other ina linear arrangement, or alternatively, may connect three or more lightemitting units 120 c to one another. However, it should be understoodthat other implementations are also possible.

At least two reflective electrode layers 131 may be connected inparallel by the connection layer 133. With this structure, the lightemitting diode has improved current spreading efficiency between aplurality of reflective electrode layers 131, thereby improving overallcurrent spreading efficiency and luminous uniformity of the lightemitting diode.

The connection layer 133 may include an electrically conductivematerial, for example, a metal. In addition, the connection layer 133may be formed of the same material as the first electrode 140.Furthermore, an upper surface of the connection layer 133 may besubstantially coplanar with an upper surface of the first electrode 140.

The upper insulation layer 153 may at least partially cover the firstelectrode 140 and the connection layer 133. The upper insulation layer153 may include a third opening at least partially exposing the firstelectrode 140 and a fourth opening at least partially exposing thesecond electrode 131.

Each of the third and fourth openings may be formed singularly or inplural. Further, in a structure wherein the third opening is disposednear one edge of the light emitting diode, the fourth opening may bedisposed near the opposite edge thereof. The third and fourth openingspartially expose the first and second electrodes 140, 131 to providepaths through which the first and second pads 161, 163 are electricallyconnected to the first and second electrodes 140, 131, respectively.

The upper insulation layer 153 may include an insulation material, forexample, SiO₂ or SiN_(x). Furthermore, the upper insulation layer 153may have a multilayer structure and may include a distributed Braggreflector in which material layers having different refractive indicesare alternately stacked one above another.

On the other hand, the upper insulation layer 153 may be formed of adifferent material from the lower insulation layer 151. For example, thelower insulation layer 151 may include SiO₂ and the upper insulationlayer 153 may include SiN_(x). Further, the lower insulation layer 151may have a greater thickness than the upper insulation layer 153. Withthe lower insulation layer 151 having a relatively thick thickness, thelight emitting structure 120 can be more effectively electricallyprotective and can prevent damage due to external moisture.

The light emitting diode may further include a first pad 161 and asecond pad 163.

The first pad 161 may be disposed on the upper insulation layer 153 andis electrically connected to a first electrode 140 through the thirdopening. The second pad 163 may be disposed on the upper insulationlayer 153 and is electrically connected to a second electrode 131through the fourth opening. With this structure, the first and secondpads 161, 163 are electrically connected to the first and secondconductive type semiconductor layers 121, 125, respectively.Accordingly, the first and second pads 161, 163 can serve as electrodesthrough which external power is supplied to the light emitting diode.

The first pad 161 and the second pad 163 are spaced apart from eachother and may include a bonding layer formed of, for example, Ti, Cr, orNi, and a highly conductive metal layer formed of, for example, Al, Cu,Ag or Au, without being limited thereto.

According to other exemplary embodiments, the light emitting diode mayfurther include a heat dissipation pad (not shown).

The heat dissipation pad may be disposed on the upper insulation layer153 and may be electrically insulated from the light emitting structure120. In addition, the heat dissipation pad may be interposed between thefirst and second pads 161, 163 and may be electrically insulatedtherefrom. The heat dissipation pad may include a material having highthermal conductivity, for example, Cu.

With the heat dissipation pad, the light emitting diode can effectivelydissipate heat generated upon light emission and can improve lifespanand reliability of a high power large flip-chip-type light emittingdiode. In addition, it is possible to prevent deterioration of the lightemitting diode caused by heat generation upon operation of the lightemitting diode. Furthermore, the heat dissipation pad is disposed on theupper insulation layer 153 to be insulated from the light emittingstructure 120, thereby preventing occurrence of electrical problems (forexample, short circuit) caused by the heat dissipation pad.

FIG. 5A to FIG. 11B are a plan view and cross-sectional viewsillustrating a method of manufacturing a light emitting diode accordingto a further exemplary embodiment of the present disclosure.

The manufacturing method described with reference to FIG. 5A to FIG. 11Bcan provide the light emitting diode as described with reference to FIG.1 to FIG. 3. Accordingly, detailed descriptions of the same componentsas those of the exemplary embodiment described in FIG. 1 to FIG. 3 willbe omitted. Thus, exemplary embodiments of the present disclosure arenot limited by the following description.

In each of FIG. 5A to FIG. 11B, are a plan view and a cross-sectionalview. In FIG. 5A to FIG. 11B, each of the cross-sectional views is takenalong line C-C of the corresponding plan view.

First, referring to FIGS. 5A and 5B, a light emitting structure 120including a first conductive type semiconductor layer 121, an activelayer 123 and a second conductive type semiconductor layer 125 areformed on a substrate 110.

The substrate 110 may be any substrate that allows growth of the lightemitting structure 120 thereon, and may include, for example, a sapphiresubstrate, a silicon carbide substrate, a silicon substrate, a galliumnitride substrate, and an aluminum nitride substrate. In this exemplaryembodiment, the substrate 110 may be a patterned sapphire substrate PSS.

The first conductive type semiconductor layer 121, the active layer 123,and the second conductive type semiconductor layer 125 may besequentially formed in the stated order. The light emitting structure120 may include a nitride semiconductor and may be formed by a typicalmethod of growing nitride semiconductors, such as MOCVD, HVPE, MBE, andthe like, which are well known to those skilled in the art. Beforegrowth of the first conductive type semiconductor layer 121, a bufferlayer (not shown) may be further grown on the substrate 110.

Next, referring to FIGS. 6A and 6B, light emitting units 120 c andsecond electrodes 131 are formed. After the light emitting units 120 care formed, the second electrodes 131 may be formed, or vice versa.

The light emitting units 120 c may be formed by forming a separationregion 128 through partial removal of the second conductive typesemiconductor layer 125 and the active layer 123. Formation of theseparation region 128 may include forming an additional contact region129. Formation of the light emitting units 120 c may include formingcontact holes 127 by removing the second conductive type semiconductorlayer 125 and the active layer 123 in some regions of the light emittingunits 120 c. In the above processes, the second conductive typesemiconductor layer 125 and the active layer 123 are removed, wherebythe first conductive type semiconductor layer 121 can be partiallyexposed.

At least two light emitting units 120 c may be formed and may bedisposed such that the additional contact region 129 is disposed in aregion between the at least two light emitting units 120 c. For example,as shown in the drawings, four light emitting units 120 c having aquadrangular planar shape may be arranged in a 2×2 matrix. With thisstructure, the additional contact region 129 may be formed in a regionin which one corner of each of the four light emitting units 120 c meetscorners of other three light emitting units 120 c. However, it should beunderstood that other implementations are also possible.

The separation region 128 partitioning the light emitting units 120 c,the additional contact region 129 and the contact holes 127 may beformed by etching and photolithography. For example, with an etchingregion defined by a photoresist pattern, the regions 128, 129 and thecontact holes 127 may be formed by dry etching such as ICP.

The contact hole 127 may be formed in a central region of each of thelight emitting units 120 c. Further, the additional contact region 129may be formed such that distances from the center of the additionalcontact region 129 to the centers of the four light emitting units 120 care substantially the same.

The second electrodes 131 may be formed by deposition of a metallicmaterial and etching, or alternatively, by deposition of the metallicmaterial and lift-off. The second electrode 131 on each of the lightemitting units 120 c may be formed to surround the contact hole 127,whereby the contact holes 127 are exposed.

The second electrodes 131 may be formed to cover most of an uppersurface of the second conductive type semiconductor layer 125 of thelight emitting units 120 c.

Next, referring to FIGS. 7A and 7B, a lower insulation layer 151 may beformed to cover the light emitting units 120 c and the second electrodes131. Further, the lower insulation layer 151 may be formed to cover sidesurfaces of the contact holes 127, particularly, side surfaces of thesecond conductive type semiconductor layer 125 and the active layer 123exposed to the side surfaces of the contact holes 127.

The lower insulation layer 151 may include first openings 151 a, 151 bpartially exposing the first conductive type semiconductor layer 121 andsecond openings 151 c, 151 d partially exposing the second electrodes131. Further, the first openings 151 a, 15 1 b may include openings 151a exposing a bottom surface of each of the contact holes 127 and anopening 151 b at least partially exposing the additional contact region129, and the second openings 151 c, 151 d may include openings 151 c forformation of a second pad 163 and openings 151 d for formation ofconnection layers 133. Locations of the second openings 151 c, 151 d maybe determined based on the location of the second pad 163 and the numberand locations of the connection layers 133.

The lower insulation layer 151 may be formed by deposition andpatterning of an insulation material such as SiO₂, or alternatively, bydeposition and lift-off.

Referring to FIGS. 8A and 8B, a first electrode 140 is formed to coverthe at least four light emitting units 120 c and the lower insulationlayer 151. In addition, the connection layers 133 may be formed toelectrically connect at least two second electrodes 131 to each other.

The first electrode 140 may be formed by deposition and patterning of ametallic material, and fills the first openings 151 a, 151 b to formohmic contact with the first conductive type semiconductor layer 121through the contact holes 127 and the additional contact region 129. Onthe other hand, the first electrode 140 is not formed on the secondopenings 151 c, 151 d. With this structure, the first electrode 140 isinsulated from the second electrode 131 and the second conductive typesemiconductor layer 125.

In addition, the first electrode 140 and the connection layers 133 maybe formed at the same time by the same deposition process. For example,the first electrode 140 and the connection layers 133 may be formed bydepositing a metallic material so as to cover the entirety of the lightemitting structure 120 and the lower insulation layer 151, followed bypatterning or lift-off so as to divide the light emitting structure 120and the lower insulation layer 151. Accordingly, the first electrode 140and the connection layers 133 may include the same material. Further, anupper surface of the first electrode 140 may be coplanar with uppersurfaces of the connection layers 135.

Next, referring to FIGS. 9A and 9B, an upper insulation layer 153 may beformed to cover at least part of the first electrode 140 and theconnection layers 133.

The upper insulation layer 153 may include third openings 153 apartially exposing the first electrode 140 and fourth openings 153 b atleast partially exposing the second electrode 131. Here, the fourthopenings 153 b may be disposed corresponding to the openings 151 cexposing the second electrodes 131. The upper insulation layer 153 maybe formed by deposition and patterning of an insulation material such asSiO₂.

Particularly, the upper insulation layer 153 is formed to fill aseparation region between the first electrode 140 and the connectionlayers 133, thereby reinforcing electrical insulation between the firstelectrode 140 and the connection layers 133.

The third openings 153 a may be disposed near one edge of the lightemitting diode and the fourth openings 153 b may be disposed near theopposite edge thereof. That is, the third and fourth openings 153 a, 153b may be formed so as to be disposed near the opposite edges of thelight emitting diode, respectively, as shown in the drawings.

Next, referring to FIGS. 10A and 10B, a first pad 161 and a second pad163 may be formed on the upper insulation layer 153. As a result, thelight emitting diode as shown in FIG. 1 to FIG. 4 can be provided.

The first pad 161 may be formed on the third openings 153 a to fill thethird openings 153 a therewith and thus can be electrically connected toa first electrodes 140. Likewise, the second pad 163 may be formed onthe fourth openings 153 b to fill the fourth openings 153 b therewithand thus can be electrically connected to second electrodes 131. Thefirst pad 161 and the second pad 163 may be used as pads for bumpconnection or SMT in order to mount the light emitting diode on asub-mount, a package, a printed circuit board, and the like.

The first and second pads 161, 163 may be formed at the same time by thesame process, for example, by photolithography and etching or lift-off.

In addition, the manufacturing method may further include separating thesubstrate 110 from the light emitting structure 120. The substrate 110can be separated or removed therefrom by physical and/or chemicalprocesses.

In addition, the manufacturing method may further include forming a heatdissipation pad 170 on the upper insulation layer 153, as shown in FIGS.11A and 11B. The heat dissipation pad 170 may be formed by a similarprocess to the process of forming the first and second pads 161, 163,for example, by plating, electroplating or deposition. Furthermore, theheat dissipation pad 170 may be formed simultaneously with the first andsecond pads 161, 163.

FIG. 12 to FIG. 16 are a plan view and cross-sectional views of a lightemitting diode according to yet another exemplary embodiment of thepresent disclosure.

FIG. 12 is a plan view of the light emitting diode. FIG. 13 is a planview of the light emitting diode, in which a first pad 161, a second pad163 and an insulation layer 260 are omitted for convenience ofdescription. FIG. 14 is a cross-sectional view taken along line A-A′ ofFIG. 13, FIG. 15 is a cross-sectional view taken along line B-B′ of FIG.13, and FIG. 16 is a cross-sectional view taken along line C-C′ of FIG.13. Detailed descriptions of the same or similar components to those ofthe exemplary embodiments described above will be omitted and thefollowing description will focus on different features of this exemplaryembodiment.

Referring to FIG. 12 to FIG. 16, the light emitting diode according tothis exemplary embodiment includes a light emitting structure 120, acurrent spreading layer 230, first electrodes 240, second electrodes250, and an insulation layer 260. In addition, the light emitting diodemay further include a substrate 110, a current blocking layer 220, afirst pad 161, and a second pad 163. The light emitting diode may have aquadrangular planar shape. In this exemplary embodiment, the lightemitting diode has a square planar shape, and may include a first sidesurface 101, a second side surface 102, a third side surface 103opposite the first side surface 101, and a fourth side surface 104opposite the second side surface 102.

The substrate 110 is similar to the substrate described with referenceto FIG. 1 to FIG. 3 and may also be omitted in this exemplaryembodiment.

The light emitting structure 120 may include a first conductive typesemiconductor layer 121, an active layer 123 disposed on the firstconductive type semiconductor layer 121, and a second conductive typesemiconductor layer 125 disposed on the active layer 123. In addition,the light emitting structure 120 may include a plurality of mesas 120 mand a separation region 128 formed between the mesas 120 m. Although thenumber and shape of the mesas 120 m are not particularly limited, thelight emitting structure 120 may include, for example, two mesas 120 m,as shown in FIG. 13. The two mesas 120 m are disposed in a substantiallysymmetrical arrangement and each of the mesas 120 m may have anelongated shape extending from the first side surface 101 towards thethird side surface 103. Accordingly, the separation region 128 may alsohave an elongated shape extending from the first side surface 101towards the third side surface 103.

The mesas 120 m may be disposed on the first conductive typesemiconductor layer 121 and include the second conductive typesemiconductor layer 125 and the active layer 123. Since the mesas 120 minclude the active layer 123, the mesas 120 m according to thisexemplary embodiment can also be defined as luminous regions like thelight emitting units 121 c of the above embodiment shown in FIG. 1 toFIG. 3. In addition, each of the mesas 120 m may include at least onecontact hole 127, through which the first conductive type semiconductorlayer 121 may be exposed. The first electrodes 240 may be electricallyconnected to the first conductive type semiconductor layer 121 throughthe at least one contact hole 127.

The number and shape of the contact holes 127 may be controlled ormodified depending upon spreading of electric current applied to thelight emitting diode and luminous patterns thereof. For example, thecontact hole 127 may be formed to extend from one side surface of themesa 120 m to a center thereof. In addition, the contact hole 127 mayinclude a main contact hole 127 a having a relatively large width and asecondary contact hole 127 b having a relatively small width.

In this exemplary embodiment, the contact hole 127 may extend from aside surface of the mesa 120 m adjacent to the first side surface 101among the side surfaces of the mesa 120 m towards the third side surface103. In addition, the contact hole 127 includes a plurality of maincontact holes 127 a and a plurality of secondary contact holes 127 b.The secondary contact holes 127 b may connect the main contact holes 127a to each other or may extend from the main contact holes 127 a. Forexample, as shown in the drawings, four main contact holes 127 a arespaced apart from one another and the secondary contact holes 127 b maybe disposed to connect the four main contact holes 127 a to one anotherand may be disposed so as to extend from the main contact holes 127 adisposed at a distal end. At least some of the main contact holes 127 amay be disposed under the first pad 161.

In this exemplary embodiment, the contact hole 127 may extend from aside surface of the mesa 120 m adjacent to the first side surface 101among the side surfaces of the mesa 120 m towards the third side surface103. In addition, the contact hole 127 includes a plurality of maincontact holes 127 a and a plurality of secondary contact holes 127 b.The secondary contact holes 127 b may connect the main contact holes 127a to each other or may extend from the main contact holes 127 a. Forexample, as shown in the drawings, four main contact holes 127 a arespaced apart from one another and the secondary contact holes 127 b maybe disposed to connect the four main contact holes 127 a to one anotherand may be disposed so as to extend from the main contact holes 127 adisposed at a distal end. At least some of the main contact holes 127 amay be disposed under the first pad 161.

Further, the mesas 120 m include the additional contact region 129disposed in the separation region 128. The first electrode 240,particularly, a third ohmic contact electrode 245 of the first electrode240, is electrically connected to the first conductive typesemiconductor layer 121 through the additional contact region 129, aswill be described below in more detail. The location of the additionalcontact region 129 may be determined such that distances from theadditional contact region 129 to the plural mesas 120 m aresubstantially constant. The additional contact region 129 may bedisposed under the first pad 161.

The current blocking layer 220 may be partially disposed on the mesa 120m. Particularly, the current blocking layer 220 may be disposedcorresponding to the second electrode 250. The current blocking layer220 may include a first current blocking layer 221 and a second currentblocking layer 223, which may be disposed at locations corresponding toa first connection electrode 251 and a second connection electrode 253of the second electrode 250, respectively. In addition, the secondcurrent blocking layer 223 may include a main current blocking layer 223a and a secondary current blocking layer 223 b which are disposed atlocations corresponding to a main electrode 253 a and an extensionelectrode 253 b of the second connection electrode 253.

The current blocking layer 220 can prevent occurrence of currentcrowding under the second electrode 250 due to direct supply of electriccurrent to the second conductive type semiconductor layer 125.Accordingly, the current blocking layer 220 may have electricalinsulation properties, may include an insulation material, and may becomposed of a single layer or multiple layers. For example, the currentblocking layer 130 may include SiO_(x) or SiN_(x), or may include adistributed Bragg reflector in which material layers having differentrefractive indices are alternately stacked one above another. Thecurrent blocking layer 220 may have light transmittance, lightreflectivity, or selective light reflectivity. Further, the currentblocking layer 220 may have a larger area than the second electrode 250formed thereon. Accordingly, the second electrode 250 may be disposedabove a region in which the current blocking layer 220 is formed.

The current spreading layer 230 may be disposed on the second conductivetype semiconductor layer 125, that is, on the mesa 120 m. Furthermore,the current spreading layer 230 may cover the current blocking layer220. The current spreading layer 230 may be electrically connected tothe second conductive type semiconductor layer 125 and may form ohmiccontact with the second conductive type semiconductor layer 125. Thecurrent spreading layer 230 may cover an substantially overall uppersurface of the mesa 120 m, and may be formed along an outer periphery ofthe upper surface of the mesa 120 m, as shown in the drawings. Whenapplied through such a current spreading layer 230, electric current canbe uniformly spread on the mesa 120 m in the horizontal direction,thereby improving current spreading of the light emitting diode. Thecurrent spreading layer 230 may be formed of a conductive material, suchas metals and conductive oxides, for example, a conductive oxide such asITO, ZnO, IZO, GZO and AZO, a light transmissive metal such as Ni/Au,and a metal such as Ni, Pt, Pd, Rh, W, Ti, Al, Mg, Ag, Cr, and Au.

In some exemplary embodiments, the current spreading layer 230 may havea multilayer structure, and may include a lower current spreading layer231 disposed on the mesa 120 m and an upper current spreading layer 233disposed on the lower current spreading layer 231.

The lower current spreading layer 231 may form ohmic contact with thesecond conductive type semiconductor layer 125. Further, the lowercurrent spreading layer 231 may be formed of a conductive oxide dopedwith a predetermined dopant, thereby reducing contact resistance at aninterface between the lower current spreading layer 231 and the secondconductive type semiconductor layer 125. For example, the lower currentspreading layer 231 may include ITO or ZnO doped with at least onedopant selected from among silver (Ag), indium (In), tin (Sn), zinc(Zn), cadmium (Cd), gallium (Ga), aluminum (Al), magnesium (Mg),titanium (Ti), molybdenum (Mo), nickel (Ni), copper (Cu), gold (Au),platinum (Pt), rhodium (Rh), iridium (Ir), ruthenium (Ru), and palladium(Pd).

The lower current spreading layer 231 may have a thickness of about 10 Åto 1,000 Å. The lower current spreading layer 231 may be doped at adoping concentration of about 0.01 at % to about 40 at %, preferablyabout 0.01 at % to about 20 at %.

The upper current spreading layer 233 may be disposed on the lowercurrent spreading layer 231. The upper current spreading layer 233 mayhave higher transmittance and lower sheet resistance than the lowercurrent spreading layer 233. For example, when the lower currentspreading layer 231 is formed of ITO doped with the dopant, the uppercurrent spreading layer 233 may have a greater thickness than the lowercurrent spreading layer 231 and may be formed of undoped ITO. Theundoped ITO has high light transmittance and a higher thickness than thedoped ITO, thereby providing lower lateral resistance, that is, lowersheet resistance.

The current spreading layer 230 may have an overall thickness of, forexample, about 10,000 Å or less, specifically about 5,000 Å to 9000 Å,more specifically about 6,000 Å or about 8000 Å, without being limitedthereto.

As such, the lower current spreading layer 231 having a relatively lowthickness and formed of ITO or ZnO doped with a metal is formed to formelectrical contact with the second conductive type semiconductor layer125, thereby improving light transmittance of the lower currentspreading layer 231 and ohmic characteristics. Further, the uppercurrent spreading layer 233 is formed to a relatively thick thicknessusing undoped ITO, thereby improving lateral current spreadingefficiency. That is, according to this exemplary embodiment, with thestructure wherein the current spreading layer 230 has a multilayerstructure including the lower and upper current spreading layers 231,233, the light emitting diode can reduce forward voltage Vf throughimprovement in ohmic characteristics and current spreading efficiency,and can improve luminous efficacy through improvement in lighttransmittance.

In some exemplary embodiments, the current spreading layer 230 may becomposed of a single layer. Here, the current spreading layer 230composed of a single layer may include a transparent conductive oxidehaving improved ohmic characteristics and light transmittance. Forexample, the current spreading layer 230 may be composed of a single ZnOlayer having higher light transmittance than ITO.

The insulation layer 260 may cover upper surfaces of the light emittingstructure 120 and the current spreading layer 230 and include openingsexposing the first and second electrodes 240, 250. Further, theinsulation layer 260 may include a lower insulation layer 261 and anupper insulation layer 263. In the following description, the lowerinsulation layer 261 and the upper insulation layer 263 will beseparately described, but are not limited thereto.

First, the lower insulation layer 261 may cover a side surface and anupper surface of the light emitting structure 120 and the currentspreading layer 230, and may include openings exposing portions of thefirst conductive type semiconductor layer 121 and the current spreadinglayer 230. The portions of the first conductive type semiconductor layer121 and the current spreading layer 230 exposed through the openings ofthe lower insulation layer 261 may be disposed corresponding to thefirst and second electrodes 240, 250. In this exemplary embodiment, aportion of the first conductive type semiconductor layer 121 exposedthrough the contact hole 127 and at least part of the additional contactregion 129 may be exposed through the openings. Here, the side surfaceof the contact hole 127 may be at least partially covered by the lowerinsulation layer 261. In addition, the main contact holes 127 a of thecontact hole 127 are exposed through the openings, and some secondarycontact holes 127 b of the contact hole 127 are exposed and the othersecondary contact holes 127 b of the contact hole 127 may be covered bythe lower insulation layer 261. Further, the portions of the currentspreading layer 230 exposed through the openings are disposed on thecurrent blocking layer 220. However, it should be understood that otherimplementations are also possible.

The lower insulation layer 261 may include an insulation material, forexample, SiO₂, SiN_(x), MgF₂, and the like. In some exemplaryembodiments, the lower insulation layer 261 can also act as a basallayer for other layers formed on the lower insulation layer 261. Forexample, in the structure wherein the upper insulation layer 263includes a distributed Bragg reflector, the lower insulation layer 261can act as a basal layer so as to allow the distributed Bragg reflectorto be stably formed thereon. When the distributed Bragg reflector has astack structure of TiO₂/SiO₂ layers alternately stacked one aboveanother, the lower insulation layer 261 may be formed of an SiO₂ layerhaving a predetermined thickness. For example, the predeterminedthickness may range from about 0.2 μm to 1.0 μm.

In order to form a distributed Bragg reflector having good quality, itis desirable that the basal layer on which the distributed Braggreflector will be deposited have good film quality and good surfacecharacteristics. Accordingly, with the lower insulation layer 261 formedto a predetermined thickness or more, the distributed Bragg reflectorcan be stably formed on the lower insulation layer 261.

The first electrode 240 is electrically connected to the firstconductive type semiconductor layer 121. The first electrode 240 isdisposed on the exposed portion of the first conductive typesemiconductor layer 121 to form ohmic contact with the first conductivetype semiconductor layer 121. Particularly, the first electrode 240 mayform ohmic contact with the first conductive type semiconductor layer121 through the contact holes 127 and also form ohmic contact with thefirst conductive type semiconductor layer 121 through the additionalcontact region 129. In addition, the first electrode 240 is electricallyconnected to the first pad 161. In this exemplary embodiment, the firstelectrode 240 may include first ohmic contact electrodes 241, secondohmic contact electrodes 243, and the third ohmic contact electrode 245.

The first ohmic contact electrodes 241 may be disposed in some maincontact holes 127 a. In addition, the first ohmic contact electrodes 241may be disposed so as to overlap a region, in which the first pad 161 isformed, in the vertical direction. That is, the first ohmic contactelectrodes 241 are disposed under the first pad 161 in the region inwhich the first pad 161 is formed. Accordingly, the first ohmic contactelectrodes 241 may contact the first pad 161. On the other hand,although the plural first ohmic contact electrodes 241 are disposed insome of the main contact holes 127 a and are spaced apart from eachother in this exemplary embodiment, it should be understood that otherimplementations are also possible. The first ohmic contact electrodes241 may also be disposed in some of the secondary contact holes 127 bunder the first pad 161, and the first ohmic contact electrodes 241disposed in the main contact holes 127 a and spaced apart from eachother may also be connected to each other.

The second ohmic contact electrodes 243 may be disposed in the maincontact holes 127 a and the secondary contact holes 127 b. In addition,the second ohmic contact electrodes 243 may extend in the extensiondirection of the contact hole 127, that is, from the first side surface101 towards the third side surface 103. Particularly, the second ohmiccontact electrodes 243 may include a main electrode 243 a disposed belowthe first pad 161 and an extension electrode 243 b disposed under aregion between the first pad 161 and the second pad 163. Accordingly,the main electrode 243 a may contact the first pad 161 and the extensionelectrode 243 b may extend towards the second pad 163. Accordingly,electrons injected through the main electrode 243 a contacting the firstpad 161 can be easily spread to the extension electrode 243 b. With thisstructure, the light emitting diode can relieve current crowding in thefirst conductive type semiconductor layer 121 disposed below the mainelectrode 243 a, thereby improving current spreading efficiency.

Further, the extension electrode 243 b may include a relatively widesection disposed in the main contact holes 127 a and a relatively narrowsection disposed in the secondary contact holes 127 b. Electric currentcan be efficiently supplied to the first conductive type semiconductorlayer 121 through the relatively narrow section of the extensionelectrode 243 b disposed in the main contact holes 127 a. Accordingly,the light emitting diode allows efficient supply of electric current tothe first conductive type semiconductor layer 121 disposed below theregion between the first pad 161 and the second pad 163, therebyimproving current spreading efficiency.

The second electrode 250 is disposed on the current spreading layer 230to be electrically connected to the current spreading layer 230.Particularly, the second electrode 250 may be disposed above the currentblocking layer 220. In addition, the second electrode 250 iselectrically connected to the second pad 163 and the current spreadinglayer 230 may be electrically connected to the second pad 163 throughthe second electrode 250. The second electrode 250 may include at leastone first connection electrode 251 and at least one second connectionelectrode 253.

The first connection electrode 251 may contact the current spreadinglayer 230 through the openings of the lower insulation layer 261. Inaddition, the first connection electrode 251 may be disposed to overlapa region, in which the second pad 163 is formed, in the verticaldirection. That is, the first connection electrode 251 is disposed underthe second pad 163 in the region in which the second pad 163 is formed.With this structure, the first connection electrode 251 may contact thesecond pad 163. In a structure wherein the second electrode 250 includesa plurality of first connection electrodes 251, the plural firstconnection electrode 251 may be spaced apart from each other. However,it should be understood that other implementations are also possible andthe plurality of the first connection electrode 251 may be connected toeach other.

At least part of the second connection electrode 253 may be disposed tooverlap a region, in which the second pad 163 is formed, in the verticaldirection. The second connection electrode 253 may include a mainelectrode 253 a disposed under the second pad 163 to contact the secondpad 163 and an extension electrode 253 b extending from the mainelectrode 253 a. The extension electrode 253 b may extend from thesecond pad 163 in a direction approaching the first pad 163. In thisexemplary embodiment, the extension electrode 253 b may extend from thethird side surface 103 towards the first side surface 101. Further, theextension electrode 253 b may extend to a portion under a region betweenthe first pad 161 and the second pad 163 and may reach a region underthe first pad 161. A portion of the extension electrode 253 b extendingto the region under the first pad 161 is electrically insulated from thefirst pad 161 by the upper insulation layer 263. As such, with thestructure wherein the second connection electrode 253 includes theextension electrode 253 b extending to the region under the first pad161, the light emitting diode can achieve efficient current spreadingunder the region between the first pad and the second pad 161, 163 andto a portion of the second conductive type semiconductor layer 125 belowthe first pad 161 while preventing current crowding in the secondconductive type semiconductor layer 125 disposed below the mainelectrode 253 a.

The extension electrode 253 b may have a narrower width than the mainelectrode 253 a. Accordingly, electric current can be efficientlysupplied from the second pad 163 to the second connection electrode 253through the main electrode 253 a and then can be efficiently spreadthrough the extension electrode 253 b. Further, in the structure whereinthe second electrode 250 includes a plurality of second connectionelectrode 253, at least part of the first electrode 240 may be disposedbetween the extension electrodes 253 b. As shown in the drawings, thefirst and second ohmic contact electrodes 241, 243 may be disposedbetween two extension electrodes 253 b and the third ohmic contactelectrode 245 may also be disposed between the two extension electrodes253 b. With this structure, the light emitting diode can achieve moreefficient current crowding.

In addition, at least part of the first electrode 240 and the secondelectrode 250 may further cover an upper surface of the lower insulationlayer 261. That is, at least part of the first and second electrodes240, 250 fill the openings of the lower insulation layer 261 and furthercover the upper surface of the lower insulation layer 261 around theopenings thereof.

The upper insulation layer 263 covers the lower insulation layer 261 andpartially covers the first electrode 240 and the second electrode 250.The upper insulation layer 263 includes openings at least partiallyexposing the first electrode 240 and the second electrode 250.

First, at least part of the first ohmic contact electrode 241 and thethird ohmic contact electrode 245 of the first electrode 240 is exposedthrough the opening of the upper insulation layer 263 and mayelectrically contact the first pad 161 through the openings thereof. Aportion of the second ohmic contact electrode 243 of the first electrode240 may be exposed through the openings of the upper insulation layer263 and the remaining portion thereof may be covered by the upperinsulation layer 263. Specifically, at least part of the main electrode243 a of the second ohmic contact electrode 243 disposed in the maincontact hole 127 a is exposed through the opening of the upperinsulation layer 263 and the extension electrode 243 b of the secondohmic contact electrode 243 is covered by the upper insulation layer263.

At least part of the first connection electrode 251 of the secondelectrode 250 is exposed through the openings of the upper insulationlayer 263 and electrically connected to the second pad 163 through theopenings thereof. A portion of the second connection electrode 253 ofthe second electrode 250 may be exposed through the openings of theupper insulation layer 263 and the remaining portion thereof may becovered by the upper insulation layer 263. Specifically, at least partof the main electrode 253 a of the second connection electrode 253 isexposed through the opening of the upper insulation layer 263 and theextension electrode 253 b thereof is covered by the upper insulationlayer 263. Accordingly, the extension electrode 253 b disposed below thefirst pad 161 is insulated from the first pad 161 by the upperinsulation layer 263.

As such, portions of the first and second electrodes 240, 250 under theregion between the first and second pads 161, 163 are covered by theupper insulation layer 263, thereby preventing electric short in theregion between the first and second pads 161, 163 due to solder orimpurities.

The upper insulation layer 263 may include an insulation material, forexample, SiO₂, SiN_(x), MgF₂, and the like. In some exemplaryembodiments, the upper insulation layer 263 may include a distributedBragg reflector. The distributed Bragg reflector may be formed byalternately stacking dielectric layers having different refractiveindices and may have, for example, a stack structure of TiO₂/SiO₂ layersalternately stacked one above the other. Each layer of the distributedBragg reflector may have an optical thickness corresponding to ¼ of aparticular wavelength, and the distributed Bragg reflector may becomposed of 4 to 20 pairs of such layers. However, it should beunderstood that other implementations are also possible. In thestructure wherein the upper insulation layer 263 is composed of multiplelayers, the uppermost layer of the upper insulation layer 263 may beformed of SiN_(x). The SiN_(x) layer exhibits good moisture resistance,thereby protecting the light emitting diode from moisture.

In the structure wherein the upper insulation layer 263 includes thedistributed Bragg reflector, the lower insulation layer 261 can act as abasal layer or an interface layer for improving quality of thedistributed Bragg reflector. For example, the lower insulation layer 261may be formed of SiO₂ to a thickness of about 0.2 μm to 1.0 μm and theupper insulation layer 263 may be composed of a distributed Braggreflector in which certain pairs of TiO₂/SiO₂ layers are repeated. Here,a layer of the upper insulation layer 263 contacting the lowerinsulation layer 261 may be a TiO₂ layer.

The distributed Bragg reflector may have relatively high reflectancewith respect to visible light. The distributed Bragg reflector may bedesigned to have a reflectance of 90% or more with respect to lightentering at an incidence angle of 0˜60° and having a wavelength of 400nm to 700 nm. The distributed Bragg reflector having such reflectancemay be provided by adjusting the kind, thickness and stacking cycles ofa plurality of dielectric layers constituting the distributed Braggreflector. Accordingly, it is possible to form a distributed Braggreflector having high reflectance with respect to light havingrelatively long wavelengths (for example, 550 nm to 700 nm) and lighthaving relatively short wavelengths (for example, 400 nm to 550 nm).

As such, the distributed Bragg reflector may include a multilayer stackstructure in order to have high reflectance with respect to light in abroad wavelength band. That is, the distributed Bragg reflector mayinclude a first stack structure in which dielectric layers having afirst thickness are stacked one above another and a second stackstructure in which dielectric layers having a second thickness arestacked one above another. For example, the distributed Bragg reflectormay include a first stack structure wherein dielectric layers having asmaller thickness than an optical thickness of ¼ of a center wavelength(about 550 nm) of visible light are stacked one above another, and asecond stack structure in which dielectric layers having a greaterthickness than the optical thickness of ¼ of the center wavelength(about 550 nm) of visible light are stacked one above another.Furthermore, the distributed Bragg reflector may further include a thirdstack structure in which dielectric layers having a greater thicknessthan the optical thickness of ¼ of the center wavelength (about 550 nm)of visible light and dielectric layers having a smaller thickness thanthe optical thickness of ¼ of the center wavelength (about 550 nm) ofvisible light are alternately stacked one above another.

As light is reflected from the distributed Bragg reflector of the upperinsulation layer 263 covering substantially the entirety of the uppersurface of the light emitting structure 120, the light emitting diodecan have improved luminous efficacy. In addition, as described above,since the current spreading layer 230 may be composed of multiple layersto exhibit relatively high light transmittance, light loss due toabsorption of light by the distributed Bragg reflector and the currentspreading layer 230 can be reduced, thereby improving luminous efficacyof the light emitting diode.

Further, the upper insulation layer 263 may partially cover the uppersurfaces of the first and second electrodes 240, 250. As shown in FIG.14 to FIG. 16, at least part of the first electrode 240 and the secondelectrode 250 may further cover the upper surface of the lowerinsulation layer 271, and the upper insulation layer 263 may furthercover at least part of the first electrode 240 and the second electrode250. Accordingly, at least part of the first electrode 240 and thesecond electrode 250 may be interposed between the lower insulationlayer 261 and the upper insulation layer 263. Accordingly, the firstelectrode 240 and the second electrode 250 can be stably secured toprevent increase in forward voltage and variation of luminous patternsdue to delamination of the electrodes 240, 250, thereby improvingelectrical and optical reliability of the light emitting diode.

Although the insulation layer 260 is illustrated as including the lowerinsulation layer 261 and the upper insulation layer 263 in thisexemplary embodiment, it should be understood that other implementationsare also possible. In some exemplary embodiments, as shown in FIG. 16,the insulation layer 260 may be composed of a single layer or may be asingle layer of a multilayer structure instead of being separatelyformed. In these exemplary embodiments, the electrodes 240, 250 may nothave a portion interposed between the insulation layers 260.

Referring again to FIG. 12 to FIG. 15, the first pad 161 and the secondpad 163 are disposed on the upper insulation layer 263. The first pad161 and the second pad 163 are electrically connected to the firstelectrode 240 and the second electrode 250, respectively. Particularly,the first pad 161 may contact parts of the first ohmic contactelectrodes 241 and the second ohmic contact electrodes 243 whilecontacting the third ohmic contact electrode 245, and the second pad 163may contact a portion of the second connection electrode 253 whilecontacting the first connection electrode 161.

In another exemplary embodiment, the light emitting diode may furtherinclude a heat dissipation pad (not shown). The heat dissipation padaccording to this exemplary embodiment is generally similar to that ofthe above exemplary embodiments, and thus a detailed description thereofwill be omitted herein.

FIGS. 18A to FIG. 25B are plan views and cross-sectional viewsillustrating a method of manufacturing a light emitting diode accordingto yet another exemplary embodiment of the present disclosure.

In each of FIGS. 18A to FIGS. 25B is a plan view and a cross-sectionalview taken along line D-D′ of the plan view. Detailed descriptions ofthe same components as those of the exemplary embodiment described inFIG. 12 to FIG. 15 will be omitted.

Referring to FIGS. 18A and 18B, a light emitting structure 120 includinga first conductive type semiconductor layer 121, an active layer 123 anda second conductive type semiconductor layer 125 is formed on a growthsubstrate 110.

The growth substrate 110 may be any substrate that allows growth of thelight emitting structure 120 thereon. For example, the growth substrate110 may include a sapphire substrate, a silicon carbide substrate, asilicon substrate, a gallium nitride substrate, and an aluminum nitridesubstrate. The light emitting structure 120 may be formed by a typicalmethod of growing nitride semiconductors, such as metal-organic chemicalvapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE), andmolecular beam epitaxy (MBE), all of which are well known to thoseskilled in the art.

Although FIGS. 18A and 18B show the growth substrate 110 and the lightemitting structure 120 corresponding to a single device, this exemplaryembodiment can also be substantially applied to a light emitting diodefabricated using a wafer including the light emitting structure 120grown on the growth substrate 110.

Referring to FIGS. 19A and 19B, a plurality of mesas 120 m is formed bypartially removing the light emitting structure 120.

The mesas 120 m may be formed by patterning, for example, by partiallyremoving the second conductive type semiconductor layer 125 and theactive layer 123 through photolithography and etching. The process offorming the mesas 120 m may include forming a contact hole 127 in eachof the mesas 120 m and a separation region 128 between the mesas 120 m.The contact hole 127 may include main contact holes 127 a and secondarycontact holes 127 b, as described above.

Next, referring to FIGS. 20A and 20B, a current blocking layer 220 isformed on the mesas 120 m. The current blocking layer 220 may be formedcorresponding to a region in which second electrodes 250 will be formed.Formation of the current blocking layer 220 may include forming a firstconnection electrode current blocking layer 221 disposed at a locationcorresponding to the first connection electrode 251 and a secondconnection electrode current blocking layer 223 disposed at a locationcorresponding to the second connection electrode 253. Further, thesecond connection electrode current blocking layer 223 may include amain electrode current blocking layer 223 a and an extension electrodecurrent blocking layer 223 b.

The current blocking layer 220 may include an insulation material andmay be formed on the mesas 120 m by a method known in the art. Forexample, the current blocking layer 220 is formed on an overall uppersurface of the light emitting structure 120 through sputtering, e-beamevaporation or plating and curing, followed by patterning through wetetching or dry etching, as shown in FIGS. 20A and 20B. Alternatively,the current blocking layer 220 may also be formed by forming aphotoresist mask, depositing a material for the current blocking layer220, and removing the photoresist through a lift-off process.

Referring to FIGS. 21A and 21B, a current spreading layer 230 is formedto cover the current blocking layer 220 on the mesas 120 m.

The current spreading layer 230 may include a conductive oxide, forexample, ITO. Further, the current spreading layer 230 may include alower current spreading layer 231 and an upper current spreading layer233. The lower and upper current spreading layers 231, 233 may besequentially formed through separate processes or may be formed throughdifferent processes. For example, the lower current spreading layer 231may be formed of ITO doped with a dopant including a metal and the uppercurrent spreading layer 233 may be formed of undoped ITO. Here, thelower and upper current spreading layers 231, 233 may be formed bye-beam evaporation or sputtering, or by different methods. The currentspreading layer 230 including the conductive oxide may be subjected topatterning through etching.

It should be understood that other implementations are also possible,and if the current spreading layer 230 is formed of a metal, the currentspreading layer 230 may be formed by plating, deposition or the like,and may be subjected to patterning through a lift-off process.

Although the current spreading layer 230 is illustrated as being formedafter formation of the mesas 120 m and the current blocking layer 220 inthis exemplary embodiment, it should be understood that otherimplementations are also possible. Alternatively, after the currentblocking layer 220 and the current spreading layer 230 are sequentiallyformed, the mesas 120 m may be formed by etching the current spreadinglayer 230 and the light emitting structure 120 in the same process.

Next, referring to FIGS. 22A and 22B, a lower insulation layer 261 isformed to partially cover the light emitting structure 120 and thecurrent spreading layer 230. Formation of the lower insulation layer 261may include depositing an insulation material such as SiO₂ on uppersurfaces of the light emitting structure 120 and the current spreadinglayer 230, and forming first to fifth openings 261 a, 261 b, 261 c, 261d, 261 e through patterning.

The first openings 261 a may expose at least part of the main contactholes 127 a, the second openings 261 b may expose at least part of themain contact holes 127 a and the secondary contact holes 127 b, and thethird opening 261 c may expose at least part of an additional contactregion 129. The fourth openings 261 d and the fifth openings 261 e maypartially expose the current spreading layer 230 and may be disposed atlocations corresponding to a first connection electrode 251 and a secondconnection electrode 253.

Referring again to FIGS. 23A and 23B, first and second electrodes 240,250 are formed such that the first to fifth openings 261 a, 261 b, 261c, 261 d, 261 e of the lower insulation layer 261 can be at leastpartially filled therewith. The first and second electrodes 240, 250 maybe formed by the same process through deposition and lift-off. When thefirst and second electrodes 240, 250 are formed in a multilayerstructure through the same process, the first and second electrodes 240,250 may have the same multilayer structure. However, it should beunderstood that other implementations are also possible. Alternatively,the first and second electrodes 240, 250 may be formed of differentmaterials in different layers through separate processes.

First to third ohmic contact electrodes 241, 243, 245 of the firstelectrode 240 may be formed to fill the first to third openings 261 a,261 b, 261 c, respectively, while covering an upper surface of the lowerinsulation layer 261 around the first to third openings 261 a, 261 b,261 c. First and second connection electrodes 251, 253 of the secondelectrode may be formed to fill the fourth and fifth openings 261 d, 261e, respectively while covering the upper surface of the lower insulationlayer 261 around the fourth and fifth openings 261 d, 261 e.

Next, referring to FIGS. 24A and 24B, an upper insulation layer 263 isformed on the lower insulation layer 261 so as to partially cover thefirst and second electrodes 240, 250. The upper insulation layer 263 maybe composed of a distributed Bragg reflector in which material layershaving different refractive indices are stacked one above another, andthe lower insulation layer 261 can act as a basal layer or aninterfacial layer for the distributed Bragg reflector. The upperinsulation layer 263 may be formed by deposition and etching processesknown in the art. The upper insulation layer 263 may include a pluralityof openings through which the first electrode 240 and second electrode250 are exposed.

Next, referring to FIGS. 25A and 25B, a first pad 161 and a second pad163 may be formed on the upper insulation layer 263. As a result, thelight emitting diode as shown in FIG. 12 to FIG. 15 can be provided.

The first pad 161 may contact the first electrode 240 through theopenings of the upper insulation layer 263. Likewise, the second pad 163may contact the second electrode 250 through the openings of the upperinsulation layer 263. The first and second pads 161, 163 may be formedat the same time by the same process, for example, by photolithographyand etching or lift-off.

In addition, the method may further include separating the substrate 110from the light emitting structure 120. The substrate 110 can beseparated or removed therefrom by physical and/or chemical processes.

FIG. 26 is an exploded perspective view of a lighting apparatus to whicha light emitting diode according to one exemplary embodiment of thepresent disclosure is applied.

Referring to FIG. 26, the lighting apparatus according to thisembodiment includes a diffusive cover 1010, a light emitting diodemodule 1020, and a body 1030. The body 1030 may receive the lightemitting diode module 1020 and the diffusive cover 1010 may be disposedon the body 1030 to cover an upper side of the light emitting diodemodule 1020.

The body 1030 may have any shape so long as the body can supply electricpower to the light emitting diode module 1020 while receiving andsupporting the light emitting diode module 1020. For example, as shownin the drawing, the body 1030 may include a body case 1031, a powersupply 1033, a power supply case 1035, and a power source connection1037.

The power supply 1033 is received in the power supply case 1035 to beelectrically connected to the light emitting diode module 1020, and mayinclude at least one IC chip. The IC chip may regulate, change orcontrol electric power supplied to the light emitting diode module 1020.The power supply case 1035 may receive and support the power supply1033, and the power supply case 1035 having the power supply 1033secured therein may be disposed within the body case 1031. The powersource connection 1037 is disposed at a lower end of the power supplycase 1035 and is coupled thereto. Accordingly, the power sourceconnection 1037 is electrically connected to the power supply 1033within the power supply case 1035 and can serve as a passage throughwhich power can be supplied from an external power source to the powersupply 1033.

The light emitting diode module 1020 includes a substrate 1023 and alight emitting diode 1021 disposed on the substrate 1023. The lightemitting diode module 1020 may be disposed at an upper portion of thebody case 1031 and electrically connected to the power supply 1033.

As the substrate 1023, any substrate capable of supporting the lightemitting diode 1021 may be used without limitation. For example, thesubstrate 1023 may include a printed circuit board having interconnectsformed thereon. The substrate 1023 may have a shape corresponding to asecuring portion formed at the upper portion of the body case 1031 so asto be stably secured to the body case 1031. The light emitting diode1021 may include at least one of the light emitting diodes according tothe exemplary embodiments described above.

The diffusive cover 1010 is disposed on the light emitting diode 1021and may be secured to the body case 1031 to cover the light emittingdiode 1021. The diffusive cover 1010 may be formed of alight-transmitting material and light orientation of the lightingapparatus may be adjusted through regulation of the shape and opticaltransmissivity of the diffusive cover 1010. Thus, the diffusive cover1010 may be modified in various shapes depending on usage andapplications of the lighting apparatus.

FIG. 27 is a cross-sectional view of one example of a display apparatusto which a light emitting diode according to one exemplary embodiment ofthe present disclosure is applied.

The display according to this embodiment includes a display panel 2110,a backlight unit supplying light to the display panel 2110, and a panelguide 2100 supporting a lower edge of the display panel 2110.

The display panel 2110 is not particularly limited and may be, forexample, a liquid crystal panel including a liquid crystal layer. Gatedriving PCBs may be further disposed at the periphery of the displaypanel 2110 to supply driving signals to a gate line. Here, the gatedriving PCBs may be formed on a thin film transistor substrate insteadof being formed on separate PCBs.

The backlight unit includes a light source module, which includes atleast one substrate and a plurality of light emitting diodes 2160. Thebacklight unit may further include a bottom cover 2180, a reflectivesheet 2170, a diffusive plate 2131, and optical sheets 2130.

The bottom cover 2180 may be open at an upper side thereof to receivethe substrate 2150, the light emitting diodes 2160, the reflective sheet2170, the diffusive plate 2131, and the optical sheets 2130. Inaddition, the bottom cover 2180 may be coupled to the panel guide. Thesubstrate may be disposed under the reflective sheet 2170 to besurrounded by the reflective sheet 2170. Alternatively, when areflective material is coated on a surface thereof, the substrate may bedisposed on the reflective sheet 2170. Further, a plurality ofsubstrates may be arranged parallel to one other, without being limitedthereto. However, it should be understood that the light source modulemay include a single substrate.

The light emitting diodes 2160 may include at least one of the lightemitting diodes according to the exemplary embodiments described above.The light emitting diodes 2160 may be regularly arranged in apredetermined pattern on the substrate. In addition, a lens 2210 may bedisposed on each of the light emitting diodes 2160 to improve uniformityof light emitted from the plurality of light emitting diodes 2160.

The diffusive plate 2131 and the optical sheets 2130 are disposed on thelight emitting diode 2160. Light emitted from the light emitting diode2160 may be supplied in the form of sheet light to the display panel2110 through the diffusive plate 2131 and the optical sheets 2130.

In this way, the light emitting diodes according to the exemplaryembodiments may be applied to direct type displays like the displayaccording to this embodiment.

FIG. 28 is a cross-sectional view of another example of the displayapparatus to which the light emitting diode according to the exemplaryembodiment of the present disclosure is applied.

The display according to this exemplary embodiment includes a displaypanel 3210 on which an image is displayed, and a backlight unit disposedat a rear side of the display panel 3210 and emitting light thereto.Further, the display includes a frame 240 supporting the display panel3210 and receiving the backlight unit, and covers 3240, 3280 surroundingthe display panel 3210.

The display panel 3210 is not particularly limited and may be, forexample, a liquid crystal panel including a liquid crystal layer. A gatedriving PCB may be further disposed at the periphery of the displaypanel 3210 to supply driving signals to a gate line. Here, the gatedriving PCB may be formed on a thin film transistor substrate instead ofbeing formed on a separate PCB. The display panel 3210 is secured by thecovers 3240, 3280 disposed at upper and lower sides thereof, and thecover 3280 disposed at the lower side of the display panel 3210 may becoupled to the backlight unit.

The backlight unit supplying light to the display panel 3210 includes alower cover 3270 partially open at an upper side thereof, a light sourcemodule disposed at one side inside the lower cover 3270, and a lightguide plate 3250 disposed parallel to the light source module andconverting spot light into sheet light. In addition, the backlight unitaccording to this exemplary embodiment may further include opticalsheets 3230 disposed on the light guide plate 3250 to spread and collectlight, and a reflective sheet 3260 disposed at a lower side of the lightguide plate 3250 and reflecting light traveling in a downward directionof the light guide plate 3250 towards the display panel 3210.

The light source module includes a substrate 3220 and a plurality oflight emitting diodes 3110 arranged at constant intervals on one surfaceof the substrate 3220. As the substrate 3220, any substrate capable ofsupporting the light emitting diodes 3110 and being electricallyconnected thereto may be used without limitation. For example, thesubstrate 3220 may include a printed circuit board. The light emittingdiodes 3110 may include at least one of the light emitting diodesaccording to the exemplary embodiments described above. Light emittedfrom the light source module enters the light guide plate 3250 and issupplied to the display panel 3210 through the optical sheets 3230. Thelight guide plate 3250 and the optical sheets 3230 convert spot lightemitted from the light emitting diodes 3110 into sheet light.

In this way, the light emitting diodes according to the exemplaryembodiments may be applied to edge type displays like the displayaccording to this exemplary embodiment.

FIG. 29 is a cross-sectional view of a headlight to which a lightemitting diode according to one exemplary embodiment of the presentdisclosure is applied.

Referring to FIG. 29, the headlight according to this exemplaryembodiment includes a lamp body 4070, a substrate 4020, a light emittingdiode 4010, and a cover lens 4050. The headlight may further include aheat dissipation unit 4030, a support rack 4060, and a connection member4040.

The substrate 4020 is secured by the support rack 4060 and is disposedabove the lamp body 4070. As the substrate 4020, any member capable ofsupporting the light emitting diode 4010 may be used without limitation.For example, the substrate 4020 may include a substrate having aconductive pattern, such as a printed circuit board. The light emittingdiode 4010 is disposed on the substrate 4020 and may be supported andsecured by the substrate 4020. In addition, the light emitting diode4010 may be electrically connected to an external power source throughthe conductive pattern of the substrate 4020. Further, the lightemitting diode 4010 may include at least one of the light emittingdiodes according to the exemplary embodiments described above.

The cover lens 4050 is disposed on a path of light emitted from thelight emitting diode 4010. For example, as shown in the drawing, thecover lens 4050 may be spaced apart from the light emitting diode 4010by the connection member 4040 and may be disposed in a direction ofsupplying light emitted from the light emitting diode 4010. By the coverlens 4050, an orientation angle and/or a color of light emitted by theheadlight can be adjusted. On the other hand, the connection member 4040is disposed to secure the cover lens 4050 to the substrate 4020 whilesurrounding the light emitting diode 4010, and thus can act as a lightguide that provides a luminous path 4045. The connection member 4040 maybe formed of a light reflective material or coated therewith. On theother hand, the heat dissipation unit 4030 may include heat dissipationfins 4031 and/or a heat dissipation fan 4033 to dissipate heat generatedupon operation of the light emitting diode 4010.

In this way, the light emitting diodes according to the exemplaryembodiment may be applied to headlights, particularly, headlights forvehicles, like the headlight according to this embodiment.

Although some exemplary embodiments have been described herein, itshould be understood by those skilled in the art that these embodimentsare given by way of illustration only, and that various modifications,variations and alterations can be made without departing from the spiritand scope of the present disclosure.

From the foregoing, it will be appreciated that specific embodiments ofthe invention have been described herein for purposes of illustration,but that various modifications may be made without deviating from thescope of the invention. Accordingly, the invention is not limited exceptas by the appended claims.

I/we claim:
 1. A light emitting diode comprising: a first conductivetype semiconductor layer; at least two light emitting units disposed onthe first conductive type semiconductor layer to be spaced apart fromeach other, each comprising an active layer, a second conductive typesemiconductor layer, and at least one contact hole formed through thesecond conductive type semiconductor layer and the active layer so as toexpose a portion of the first conductive type semiconductor layer; anadditional contact region disposed between the light emitting units andpartially exposing the first conductive type semiconductor layer; afirst electrode forming ohmic contact with the first conductive typesemiconductor layer through the contact hole of each light emitting unitand the additional contact region; a second electrode disposed on eachof the light emitting units and forming ohmic contact with the secondconductive type semiconductor layer; and a lower insulation layercovering a side surface of the first conductive type semiconductorlayer, the light emitting units, and the second electrode, wherein thelower insulation layer is shaped to include a first opening exposing thecontact hole and the additional contact region and a second openingpartially exposing the second electrode, the first and second electrodebeing insulated from each other.
 2. The light emitting diode accordingto claim 1, wherein the light emitting diode comprises at least fourlight emitting units and the additional contact region is disposed in aregion surrounded by the at least four light emitting units.
 3. Thelight emitting diode according to claim 2, wherein the additionalcontact region is disposed in a region in which corners of each of theat least four light emitting units meet.
 4. The light emitting diodeaccording to claim 2, wherein distances from a center of the additionalcontact region to centers of the at least four light emitting units arethe same.
 5. The light emitting diode according to claims 1, wherein thecontact hole is disposed in a central region of each of the lightemitting units.
 6. The light emitting diode according to claim 1,further comprising: one or more connection layers electricallyconnecting the second electrode disposed on one of the light emittingunits to the second electrode disposed on another light emitting unitadjacent to the one light emitting unit.
 7. The light emitting diodeaccording to claim 1, wherein the first electrode covers at least partof the lower insulation layer and contacts the first conductive typesemiconductor layer through the first opening.
 8. The light emittingdiode according to claim 7, wherein the first electrode further coversthe first conductive type semiconductor layer and side surfaces of thelight emitting units and is insulated by the lower insulation layer. 9.The light emitting diode according to claim 1, further comprising: anupper insulation layer at least partially covering the first electrode,wherein the upper insulation layer comprises a third opening partiallyexposing the first electrode and a fourth opening partially exposing thesecond electrode.
 10. The light emitting diode according to claim 9,further comprising: a first pad disposed on the third opening andelectrically connected to the first electrode; and a second pad disposedon the fourth opening and electrically connected to the secondelectrode.
 11. The light emitting diode according to claim 10, furthercomprising: a heat dissipation pad disposed on the upper insulationlayer.
 12. The light emitting diode according to claim 11, wherein theheat dissipation pad is disposed between the first pad and the secondpad.
 13. A method of manufacturing a light emitting diode, comprising:forming a first conductive type semiconductor layer, an active layer anda second conductive type semiconductor layer on a substrate; forming atleast two light emitting units each comprising the second conductivetype semiconductor layer, the active layer and contact holes bypartially removing the second conductive type semiconductor layer andthe active layer; forming an additional contact region disposed in aregion between the light emitting units; forming a second electrode oneach of the light emitting units so as to form ohmic contact with thesecond conductive type semiconductor layer; forming a lower insulationlayer covering a side surface of the first conductive type semiconductorlayer, the light emitting units, and the second electrodes; and forminga first electrode forming ohmic contact with the first conductive typesemiconductor layer through the contact holes and the additional contactregion, wherein the contact holes are formed through the secondconductive type semiconductor layer and the active layer so as to exposea portion of the first conductive type semiconductor layer, the firstconductive type semiconductor layer is exposed to a lower side of theadditional contact region, and the lower insulation layer comprisesfirst openings exposing the contact holes and the additional contactregion, and second openings partially exposing the second electrodes.14. The method of manufacturing a light emitting diode according toclaim 13, wherein the light emitting units comprise at least four lightemitting units, and the additional contact region is disposed in aregion surrounded by the at least four light emitting units.
 15. Themethod of manufacturing a light emitting diode according to claim 14,wherein the additional contact region is disposed in a region in whichcorners of each of the at least four light emitting units are disposed.16. The method of manufacturing a light emitting diode according toclaim 13, further comprising: forming one or more connection layerselectrically connecting the second electrode disposed on one of thelight emitting units to the second electrode disposed on another lightemitting unit adjacent to the one light emitting unit.
 17. The method ofmanufacturing a light emitting diode according to claim 16, wherein theconnection layers are formed simultaneously with the first electrode.18. The method of manufacturing a light emitting diode according toclaim 13, wherein the forming of the first electrode comprises fillingthe first openings with the first electrode such that the firstelectrode contacts the first conductive type semiconductor layer throughthe first openings.
 19. The method of manufacturing a light emittingdiode according to claim 13, further comprising: forming an upperinsulation layer at least partially covering the first electrode afterformation of the first electrode, wherein the upper insulation layercomprises a third opening partially exposing the first electrode and afourth opening partially exposing the second electrode.
 20. The methodof manufacturing a light emitting diode according to claim 19, furthercomprising: forming a first pad on the third opening so as to beelectrically connected to the first electrode and a second pad on thefourth opening so as to be electrically connected to the secondelectrode.